In semiconductor, contacts can form in openings (or vias) in a dielectric layer to electrically connect contacts above and/or below the dielectric layer to implement internal connections among different layers such as metal layers in an integrated circuit. When critical dimension (CD) in the integrated circuit becomes smaller and smaller, the size of the contacts become smaller. Mask defect and flare effect can occur, when a positive tone developer is used to develop a positive tone photoresist, a pattern of which is used to make contacts.